package com.tangding.common.utils;

import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.SecretKeySpec;

import com.tangding.common.exception.GException;
import com.tangding.common.tools.ErrorConstants;

/**
 * @description 
 *
 * @author Ranger
 * @version 2017年12月13日_下午2:40:11
 *
 */
public class AES128 {

    // 加密
    public static String Encrypt(String sSrc, String sKey) throws GException {
        try {
			if (sKey == null) {
			    System.out.print("Key为空null");
			    return null;
			}
			// 判断Key是否为16位
			if (sKey.length() != 16) {
			    System.out.print("Key长度不是16位");
			    return null;
			}
			byte[] raw = sKey.getBytes("utf-8");
			SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
			Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");//"算法/模式/补码方式"
			cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
			byte[] encrypted = cipher.doFinal(sSrc.getBytes("utf-8"));

			return Base64.encode(encrypted);//此处使用BASE64做转码功能，同时能起到2次加密的作用。
		} catch (InvalidKeyException | UnsupportedEncodingException | NoSuchAlgorithmException | NoSuchPaddingException
				| IllegalBlockSizeException | BadPaddingException e) {
			throw new GException(ErrorConstants.ERR_ENCODE_AES_128);
		}
    }

    // 解密
    public static String Decrypt(String sSrc, String sKey) throws GException {
        try {
            // 判断Key是否正确
            if (sKey == null) {
                System.out.print("Key为空null");
                return null;
            }
            // 判断Key是否为16位
            if (sKey.length() != 16) {
                System.out.print("Key长度不是16位");
                return null;
            }
            byte[] raw = sKey.getBytes("utf-8");
            SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
            Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
            cipher.init(Cipher.DECRYPT_MODE, skeySpec);
            byte[] encrypted1 = Base64.decode(sSrc);//先用base64解密
            byte[] original = cipher.doFinal(encrypted1);
            String originalString = new String(original,"utf-8");
            return originalString;
        } catch (Exception ex) {
            throw new GException(ErrorConstants.ERR_DECODE_AES_128);
        }
    }

    public static void main(String[] args) throws Exception {
        /*
         * 此处使用AES-128-ECB加密模式，key需要为16位。
         */
        String cKey = "1234567890123456";
        // 需要加密的字串
        String cSrc = "www.gowhere.so";
        System.out.println(cSrc);
        // 加密
        String enString = AES128.Encrypt(cSrc, cKey);
        System.out.println("加密后的字串是：" + enString);

        // 解密
        String DeString = AES128.Decrypt(enString, cKey);
        System.out.println("解密后的字串是：" + DeString);
        
        System.out.println(Utils.randomString(16));
    }
}